There are various causes of water leaks in a bathroom design, including bad plumbing, faulty seals around the bathtub and shower pan, and badly hung ceramic tiles. However, other factors regarding waterproofing techniques can exacerbate problems.
“A lack of knowledge by contractors and poor product choice are normally the reasons behind leaking bathrooms,” says Trent Moreland, general manager for Shower Repairs Plus. “Failure can be attributed to many careless factors such as not covering the membrane during and after curing to prevent any scuffing or penetration should another trade enter the area.
“After all, look at the cost of placing new rubber underlay over your floor membrane (which you are required to guarantee), in comparison to the cost of rectifying any failure issues which arise after occupancy.”
Moreland says that in new developments, the failure of sub- contractors to ensure that the finished floor levels are ascertained prior to the fixing of the water stops, as well as to ensure leak control flanges and puddle flanges are recessed into the floor substrate, is often a recipe for disaster. “Adequate substrate fall to the waste prior to any application of membranes, in many cases, causes membrane emulsification,” he says.
Bond breaking is another step that is often overlooked and contributes to membrane failures due to movement. “But movement is not a contributing factor if the bond breaking has been applied correctly in conjunction with an appropriate membrane material and application,” Moreland says.
The Shower Repair Plus answer to waterproofing is the DiaoSeal, which comprises various application sealers, modified grout replacement and engineered tooling preparation to ensure two-part epoxy derivative bonding to all junctions. It is injected into the wall tile and floor tile junction, wall tile and wall tile internal corners and any other tile junction within the shower recess.
“It fills any existing cracks and voids, has a tolerance for movement and is engineered to change its characteristics with temperature changes and under water so it will not shear, unlike a ridged epoxy if further expansion should occur,” says Moreland.
Megasealed Bathrooms offer a similar alternative with its chemical epoxy derivative two-part compound (no silicon used) that substitutes grout. The company states that it is a strong sealant which fills the gaps between the floor and the wall, even if further expansion should occur.
Meanwhile, Victorian company Waterproof It recommends Aquathane XR, a fibre reinforced latex-based waterproof membrane with advanced stretch qualities and fast drying time. “Many cheaper membrane products on the market have little or no stretch qualities, and often there is no evidence of caulking or taping,” says Alan Patterson of Waterproof It. “When some structural movement is present, the membrane will often break, allowing water to penetrate through.”
Application, says Patterson, occurs after caulking and taping. “A suitable primer must be applied by a brush or roller to allow correct adhesion to the membrane. Once this has dried, we apply one coat of quality membrane with a brush in one direction, and when dry we apply a liberal second coat in the opposite direction. The membrane must be then left to cure for the manufacturer’s nominated time before tiling.”
All agree that like many products on the market, they can only be as good as the preparation that is undertaken. “Surface preparation is paramount,” emphasises Patterson. “Floors and walls must be thoroughly cleaned and free from loose particles before the primer and membrane is applied. If this does not happen, there will be non adhesion in certain areas.”
Whilst Waterproof It’s products are designed to be applied over ceramic underlay, if there is a concrete floor, it will be necessary to fill any holes or cracks in the concrete prior to waterproofing. Shower Repairs Plus’ DiaoSeal can be applied to all ceramic floors and walls, including marble, granite, limestone and terracotta tiles, and tiles do not need to be removed in order to apply the product.
Patterson, however, states that he would normally recommend the removal of tiles. “There may be damaged substrate behind the tiles or there may be some loose or uneven tiles,” he says.
Jeff Thompson, technical director for Wrimco Waterproofing, which supplies the water-based two-part liquid/cement co- polymer membrane with fibrous reinforcement, Duromastic ACS-2, agrees. He says “Normally it is best practice to remove tiles to apply the product, especially if the membrane has failed. You can then prevent any leaks with new tiles if you then seal their surface.”
Thompson adds that it is a good idea to seal the mortar-bed as well as the concrete, especially when using light-coloured tiles such as marble. “Mortar is very porous and can become saturated with water, which can then become very alkaline. This moisture has the potential to seep through the joints and stain the tiles. Sealing the mortar-bed will prevent the potential for this discoloration,” he says.
Sealing the surface of the tiles in this way will require reapplication of the waterproofing product only about every seven years, says Thompson.
Meanwhile, Moreland claims: “With our superior preparation prior to the application of DiaoSeal, Shower Repairs Plus has to date not had to replace one of our seals”.
Wrimco’s Thompson says that in addition to specifying the best materials for the job, in the case of new builds, “it is very helpful if architects set down the level of the bathroom floor lower than the rest of the building. In timber-structured buildings, it is easy to drop the floor a small amount — around 30 mm — in order to help prevent water leakage. The same goes for the shower area, instead of having it flush with the rest of the room.”
Architects should also block the drains and do a flood test following bathroom construction, he advises. “They should also look at the materials being used within the wet area and take into consideration the porosity of the tile or stone being considered,” says Moreland.
“Adequate on-site supervision is crucial to ensure bathrooms are not later prone to leaking. And it’s important that tradies, or even the home owner themselves, is not allowed to enter a wet area after the application of a membrane.”
